Valve bridge

ABSTRACT

There is provided herein a valve mechanism for an internal combustion engine comprising a rocker arm and a valve bridge. There is also described herein a valve bridge.

RELATED APPLICATIONS

This application claims priority to U.S. Application No. 61/319,022 filed on Mar. 30, 2010, the contents all of which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The field of the invention generally relates to a valve bridge and valve bridge mechanism of an internal combustion engine.

BACKGROUND OF THE INVENTION

Internal combustion engines typically actuate valves on engine cylinders using an actuated rocker arm acting through a valve bridge. In operation, for example, a cam shaft-associated push rod actuates the rocker arm, which in turn actuates the valve through the valve bridge. Intake valves admit fuel and air into the cylinder, and exhaust valves allow combustion gas to escape from the cylinder. Valve actuation is required in order for the engine to produce power.

As the rocker arm pivots during engine operation, the rocker arm exerts force upon the valve bridge, which in turn actuates valve movement in a particular cylinder. It is desirable for there to be an efficient transfer of force from the rocker arm to the valve bridge and in turn to the valve stems.

There remains a need for an improved valve engine mechanism and/or valve bridge.

This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should it be construed, that any of the preceding information constitutes prior art against the present invention.

SUMMARY OF THE INVENTION

In an aspect of the present invention there is provided a valve bridge and valve bridge mechanism for an internal combustion engine.

In accordance with one aspect of the present invention there is provided a valve bridge, comprising: a bridge having a joint disposed in a central portion of said bridge; and a pivot member disposed within said joint, said pivot member comprising an abutment surface for cooperative association with a surface on a rocker arm and an outer surface portion configured for rotation within said joint, wherein said bridge is configured to engage two engine valves

In accordance with another aspect of the present invention there is provided a valve bridge, comprising: a bridge having a first joint and a second joint disposed in a central portion of said bridge, said first and second joints are in communication; a first pivot member disposed in said first joint and a second pivot member disposed in said second joint, said first pivot member comprising a first abutment surface for cooperative association with a surface on a rocker arm, a second abutment surface, and an outer surface portion configured for rotation within said first joint, said second pivot comprising an outer surface configured for rotation within said second joint and which cooperates with said second abutment surface of said first pivot member so as to restrain rotation of said first pivot member, wherein said bridge is configured to engage an engine valve.

In accordance with another aspect of the present invention, there is provided a valve bridge, comprising: a bridge having a joint disposed in a central portion of said bridge; an abutment member positioned on the inner surface of said joint; and a pivot member disposed within said joint, said pivot member comprising a first abutment surface for cooperative association with a surface on a rocker arm, an outer surface portion configured for rotation within said joint, and a second abutment surface configured to restrain rotation of said pivot member within said join, wherein said bridge is configured to engage two engine valves.

In accordance with another aspect of the present invention, there is provided a valve train mechanism, comprising: a rocker arm having a joint disposed at a first end of said rocker arm; a pivot member disposed within said joint, said pivot member comprising an abutment surface and an outer surface portion configured for rotation within said joint; and a valve bridge comprising a surface disposed on a central portion of said valve bridge configured for cooperative association with said abutment surface on said pivot member; wherein said bridge is configured to engage an engine valve.

In accordance with another aspect of the present invention, there is provided valve train mechanism, comprising: a rocker arm having a first end comprising a first joint and a second joint disposed at a first end of said rocker arm, said first and second joints are in communication; a first pivot member disposed in said first joint and a second pivot member disposed in said second joint, said first pivot member comprising an first abutment surface, a second abutment surface, and an outer surface portion configured for rotation within said first joint, said second pivot member comprising an outer surface configured for rotation within said second joint and which cooperates with said second abutment surface of said first pivot member so as to restrain rotation of said first pivot member; and a valve bridge comprising a surface in a central portion of said valve bridge, for cooperative association with said first abutment surface of said first pivot member, wherein said valve bridge is configured to engage an engine valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

FIG. 1 illustrates a partial cross-sectional view of a rocker arm and valve bridge of the present invention (Panel A), a cross section view of a pivot member of the present invention (Panel B) is a cross sectional view of an example of a pivot member of the present invention, and (Panel C) a partial cross sectional view of a valve bridge of the present invention in which the pivot member is not present;

FIG. 2 (panel A) illustrates a partial cross-sectional view of a valve bridge of the present invention, in which the pivot member is not present, and (Panel B) a cross sectional view of a valve bridge of the present invention in which the pivot member is present (Panel B);

FIG. 3 illustrates partial cross-section views (Panel A & B) of a valve bridge of the present invention;

FIG. 4 illustrates a partial cross-section view of a valve bridge of the present invention;

FIG. 5 illustrates a partial cross-sectional views (Panel A & B) of a valve bridge of the present invention;

FIG. 6 illustrates a partial cross-section view of a valve bridge of the present invention;

FIG. 7 illustrates a partial cross-sectional view of a rocker arm and valve bridge of the present invention in a first position (Panel A—valves closed) and a second position (Panel B—valves opened);

FIG. 8 illustrates a partial cross-section view of a valve bridge of the present invention;

FIG. 9 illustrates a partial cross-sectional view of an alternate embodiment of a rocker arm and valve bridge of the present invention;

FIG. 10 illustrates a partial cross-sectional view of an alternate embodiment of a rocker arm and valve bridge of the present invention; and

FIG. 11 illustrates a partial cross-sectional view of an alternate embodiment of a rocker arm and valve bridge of the present invention.

In the Detailed Description that follows, the numbers in bold face type serve to identify the component parts that are described and referred to in relation to the drawings depicting various embodiments of the invention. It should be noted that in describing various embodiments of the present invention, the same reference numerals have been used to identify the same of similar elements. Moreover, for the sake of simplicity, parts have been omitted from some figures of the drawings.

DETAILED DESCRIPTION

Internal combustion engines typically actuate valves on engine cylinders using an actuated rocker arm(s) acting through a valve bridge. In operation, for example, a cam shaft-associated push rod actuates the rocker arm, which in turn actuates the valve through the valve bridge. Intake valves admit fuel and air into the cylinder, and exhaust valves allow combustion gas to escape from the cylinder. Valve actuation is required in order for the engine to produce power.

Referring to the drawings, and as described herein, there is provided a valve bridge and a valve bridge mechanism, operable to actuates the valves of an engine.

Also as referring to the drawings, and as described herein, there is provided a valve bridge and a valve bridge mechanism for an internal combustion engine of the type comprising a rocker arm.

It will be appreciated that a variety of valve trains exist. It will be appreciated that the valve bridge and valve bridge mechanism of the present application may be applied to the other types of valve train.

One embodiment of the present invention is described in FIGS. 1 to 4.

In FIG. 1 Panel A, rocker arm 2 is rotationally or pivotally mounted on a rocker shaft (not shown but generally noted by 4). The configuration of rocker arm 2 and the arrangement of rocker arm 2 and rocker shaft 4 are well known to the skilled worker. In some examples, rocker arm 2 is configured to pivot on a pivot pin. In some examples, the rocker shaft of pivot pin is secured to a bracket mounted on the cylinder head. The size of rocker arm 2 is determined by the intended use, needs of the application and/or manufacturing requirements, which can include the location of the intake and exhaust valves in relation to the rocker arm assembly. Rocker arms can be the same or different sizes, depending on the engine application. A variety of rocker arm assemblies and configurations may be used. For example, one or more rockers arm may be cooperatively mounted on a rocker carrier, which may be mounted on an engine.

As shown in FIG. 1, rocker arm 2 has a first end 8 configured for attachment to pushrod 10, and a second end 12 which includes surface 14.

In the embodiment of FIGS. 1-4, valve bridge 6 comprises bridge 32 having joint 16 formed in bridge 32. Joint 16 defines a recess or cavity in bridge 32 configured to receive pivot member 24. Desirably, as shown, joint 16 is disposed in a central portion of bridge 32. Valve bridge 6 further comprises bores 18, 18′ at ends 20,20′ of bridge 32. Bores 18,18′ are configured to engage valve stems 22,22′. Bridge 32 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

Valve bridge 6 further comprises pivot member 24 disposed in joint 16. Pivot member 24 comprises abutment surface 26 configured for cooperative association with surface 14 on rocker arm 2. Desirably, surface 14 and abutment surface 26 have a complementary shape or configuration which permit cooperative association between pivot member 24 and bridge 32. In a specific example, both abutment surface 26 and surface 14 are generally planar.

Pivot member 24 further comprises curved portion 28 configured so as to permit rotation of pivot member 24 within joint 16. In the example of FIG. 1, curved portion 28 is generally spherical. Pivot member 24 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

As shown in FIG. 1, joint 16 comprises inner surface 30, which in this Figure comprises a curved or spherical portion. Inner surface 30 may be a variety of shapes or configurations, so long as pivot member 24 is able to rotate within joint 16.

In FIG. 1, inner surface 30 of joint 16 is generally U-shaped, comprising cylindrical wall 30 a, which in this example are generally planar defining a cylinder, and curved base 30 b.

FIG. 2 depicts another example of bridge 32 in which inner surface 30 of joint 16 comprises planar surfaces. In the example of FIG. 2, inner surface 30 of joint 16 comprises walls 30 a, which in this example are generally planar defining a cylinder, and a generally conical base comprising walls 30 c. Inner surface 30 is obtained from a standard drilling operation and coining the bottom surface with a sphere having generally the same diameter as the joint 16. Coining of the bottom surface improves the contact between the pivot member and the joint.

FIG. 3 Panel A depicts another example of joint 16 in which inner surface 30 is generally conical and comprises two generally planar surfaces 30 d, FIG. 3 Panel B depicts another example of joint 16 in which inner surface 30 comprises a generally curved surface that corresponds to the shape of spherical portion 28 of pivot member 24. In each of the examples depicted in FIG. 3, Panel A or Panel B, the configuration of inner surface 30 is obtained from standard operations, as is known to the skilled worked.

FIG. 4 depicts an alternate embodiment of valve bridge 6. In FIG. 4, bridge 32 of valve bridge 6 further comprises retaining means 200 configured to retain pivot member 24 within joint 16. In the example of FIG. 4, retaining means 200 are integral with bridge 32. In another example (not shown), retaining means 200 are fixedly or removeably attached to bridge 32.

In the example of FIG. 4, said retaining means are disposed at the aperture of said joint; the aperture of joint 16 defined by retaining means 200 (generally indicated by line d2) is smaller than the diameter of pivot member 24 (generally indicated by line d1) and so retains pivot member 24 within joint 16.

Retaining means 200 can be formed in a variety of ways. In one example, the retaining means 200 are machined in place on bridge 32 after pivot member 24 is placed in joint 16.

In another example, retaining means 200 are formed prior to insertion of pivot member 24 in joint 16. In this example, the portion of bridge 32 that defines the aperture of joint 16 is elasto-plastically deformable. The aperture of joint 16 (generally indicated by line d2) as defined by retaining means 200 is sized to be smaller than the diameter pivot member 24 (generally indicated by line d1). Pivot member 24 is pushed through the elasto-plastically deformable aperture defined by retaining means 200 so as to place pivot member 24 within joint 16. Insertion of pivot member 24 causes the elasto-plastically deformable material to deform and reform (the elastic component of the deformation is recovered after the passage of the pivot member) once pivot member 24 is inserted. Thus, once pivot member 24 is inserted, retaining means 200 reform to their initial size, and thereby reduce the size of the aperture so as to re-form retaining means 200. Following insertion of pivot member 24 the resulting aperture defined by retaining means 200 (generally indicated by line d2) is smaller than the diameter of pivot member 24 (generally indicated by line d1). The size and/or shape of joint 16 remains sufficient to permit rotation of pivot member 24 within joint 16.

In the specific example of FIG. 4, surface 30 of joint 16 comprises walls 30 a, which in this example are generally planar, and a generally conical base comprising walls 30 c. It will be appreciated that joint 16 and inner surface 30 may be a variety of configurations such pivot member 24 rotates within joint 16, and such that retaining means 200 retains pivot member 24 within joint 16.

In operation, pivot member 24 pivots in joint 16 around inner surface 30 as rocker arm 2 is actuated. It will be understood that pivot member 24 rotates freely and moves within joint 16 so as to translate the force of rocker arm 2 into valve bridge 6 during engine operation.

Thus, as rocker arm 2 pivots during engine operation, rocker arm 2 exerts force on valve bridge 6, which in turn actuates valve movement in a cylinder (not shown).

In some examples, operative association of a cam shaft though, for example, a cam follower, pushrod, and the like, results in repeated movement of rocker arm 2 so as to cause a swinging movement of rocker arm 2.

The pivoting movement of rocker arm 2 alternatively exerts a force on valve bridge 6. As rocker arm 2 pivots, surface 14 of rocker arm 2 associates with abutment surface 26 of pivot member 24 so as translate the force from rocker arm 2 to bridge 32, so as to and causes valves, which are in contact with valve bridge 6 on their stem, to open. Thus, rotation of pivot member 24 within joint 16 permits the vertical motion of rocker arm 2 to be translated into bridge 32 during engine operation. In some examples, when rocker arm 2 is released, the valves are pushed up by the force of valve-shutting springs and close.

The valve bridge and valve bridge mechanism of the present invention enables the rocker arm to operate two valves simultaneously.

An alternate embodiment of valve bridge 6 is depicted in FIGS. 5-7.

In FIGS. 5-7, valve bridge 6 comprises bridge 32 having first joint 100 and second joint 102. First joint 100 and second joint 102 are in communication. First joint 100 defines a recess or cavity in bridge 32 configured to receive first pivot member 104. Second joint 102 defines a recess or cavity configured to receive second pivot member 120. Desirably, as shown in FIGS. 5-7, first joint 100 and second joint 102 are disposed in a central portion of bridge 32. As with the previous embodiments, valve bridge 6 further comprises bores 18,18′ at ends 20,20′ of bridge 32. Bores 18,18′ are configured to engage valve stems 22,22′. Bridge 32 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

Valve bridge 6 further comprises first pivot member 104 disposed in first joint 100 and second pivot member 120 disposed in second joint 102.

First pivot member 104 comprises first abutment surface 106 which cooperates with surface 14 on rocker arm 2. In a specific example, both first abutment surface 106 and surface 14 are generally planar. The complementary shape of first abutment surface 106 and surface 14 facilitate cooperation between the two parts. First pivot member 104 further comprises second abutment surface 108. In the example of FIGS. 5-7, second abutment surface 108 is generally planar. First pivot member 104 further comprises curved or spherical portion 110 configured so as to permit rotation of pivot member 104 within first joint 100. First pivot member 104 can be made from a variety of materials, including but not limited to steel cast iron or aluminium.

As shown in FIGS. 5 and 7, first joint 100 comprises first inner surface 112, which is generally curved or spherical. Inner surface 112 may be a variety of shapes, so long as first pivot member 104 is able to rotate with first joint 100.

FIG. 6 depicts another example of first inner surface 112 of first joint 100 comprising planar surfaces. In FIG. 6, inner surface 112 comprises walls 112 a which are generally planar and generally conical walls 112 b.

As shown in FIGS. 5-7, valve bridge 6 further comprises second pivot member 120 disposed in second joint 102. Outer surface 122 of second pivot member 120 is generally curved and cooperates with second abutment surface 108 of first pivot member 104.

In one example outer surface 122 is configured so as to permit rotation of second pivot member 120 within second joint 102. In another example, pivot member 120 does not rotate within second joint 102.

Second joint 102 comprises second inner surface 130, which comprises generally planar surfaces. Inner surface 130 comprises walls 130 a and generally conical walls 130 b.

Pivot member 120 can be a variety of shapes, so long as pivot member 120 is able to cooperate with second abutment surface 108 and restrain rotation of first pivot member 104. The restraint to the rotation of first pivot member 104 helps preventing or minimizing miss assembly of valve bridge 6 in the engine. It will be appreciated that the restraint to rotation of first pivot member 104 does not interfere with the rotation of first pivot member 104 within the angle of rotation required during normal engine operation.

Second pivot member 120 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

FIG. 7 depicts another example which further comprises conduit 400 within bridge 32 that is in communication with second joint 102 and the surface of bridge 32. Conduit 400 is sized to permit a tool (not show) to be inserted through conduit 400 and remove first pivot member 104 and/or second pivot member 120 from first joint 100 and/or second joint 102.

As with the example of FIG. 4, in another example, in the embodiment of FIGS. 4-7, bridge 32 of valve bridge 6 further comprises retaining means (not shown) configured to retain pivot member 104 within first joint 100. In one example (not shown), retaining means are integral with bridge 32. In another example (not shown), retaining means are fixedly or removedly attached to bridge 32.

In one example, said retaining means are disposed at the aperture of said joint; the aperture of joint 100 defined by retaining means is smaller than the diameter of pivot member 104 and so retains pivot member 104 within first joint 100.

Retaining means can be formed in a variety of ways. In one example, the retaining means are machined in place on bridge 32 after pivot member 104 is placed in first joint 100.

In another example, retaining means are formed prior to insertion of pivot member 104 in joint 100. In this example, the portion of bridge 32 that defines the aperture of joint 100 is elasto-plastically deformable. The aperture of joint 100 as defined by retaining means is sized to be smaller than the diameter pivot member 104. Pivot member 104 is pushed through the elasto-plastically deformable aperture defined by retaining means so as to place first pivot member 104 within first joint 100. Insertion of pivot member 104 causes the elasto-plastically deformable material to deform and reform (the elastic component of the deformation is recovered after the passage of the pivot member) once pivot member 104 is inserted. Thus, once pivot member 104 is inserted, retaining means reform to their initial size, and thereby reduce the size of the aperture so as to re-form retaining means. Following insertion of pivot member 104 the resulting aperture defined by retaining means is smaller than the diameter of pivot member 104. The size and/or shape of joint 100 remains sufficient to permit rotation of pivot member 104 within joint 100.

FIG. 8 depicts another embodiment of the present invention.

In FIG. 8, valve bridge 6 comprises bridge 32 having first joint 100 formed in bridge 32. First joint 100 defines a recess or cavity in bridge 32 configured to receive first pivot member 104. Desirably, as shown in FIG. 8, first joint 100 is disposed in a central portion of bridge 32. As with the previous embodiment, valve bridge 6 further comprises bores 18,18′ at ends 20,20′ of bridge 32. Bores 18,18′ are configured to engage valve stems 22,22′. Bridge 32 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

Valve bridge 6 further comprises first pivot member 104 disposed in first joint 100.

First pivot member 104 comprises first abutment surface 106 which cooperates with surface 14 on rocker arm 2. In a specific example, both first abutment surface 106 and surface 14 are flat. The complementary shape of first abutment surface 106 and surface 14 facilitate cooperation between the two parts. First pivot member 104 further comprises second abutment surface 108. In the example of FIG. 8, second abutment surface 108 is flat. First pivot member 104 further comprises curved or spherical portion 110 configured so as to permit rotation of pivot member 104 within first joint 100. First pivot member 104 can be made from a variety of materials, including but not limited to steel cast iron or aluminium.

As shown in FIG. 8, first joint 100 comprises first inner surface 112, which is generally planar. Inner surface 112 may be a variety of shapes, so long as first pivot member 104 is able to rotate with first joint 100.

As shown in FIG. 8, valve bridge 6 further comprises second abutment member 300 fixedly disposed on first inner surface 112 in first joint 100.

Outer surface 302 of second abutment member 300 is generally curved and cooperates with second abutment surface 108 of first pivot member 104. Abutment member 300 can be a variety of shapes, so long as abutment member 300 is able to cooperate with second abutment surface 108 and restrain rotation of first pivot member 104. The restraint to the rotation of first pivot member 104 helps preventing or minimizing miss assembly of valve bridge 6 in the engine.

As with the previous examples of in another example, in the embodiment of FIG. 8, bridge 32 of valve bridge 6 further comprises retaining means (not shown) configured to retain pivot member 104 within first joint 100. In one example (not shown), retaining means are integral with bridge 32. In another example (not shown), retaining means are fixedly or removedly attached to bridge 32.

In one example, said retaining means are disposed at the aperture of said joint; the aperture of joint 100 defined by retaining means is smaller than the diameter of pivot member 104 and so retains pivot member 104 within first joint 100.

Retaining means can be formed in a variety of ways. In one example, the retaining means are machined in place on bridge 32 after pivot member 104 is placed in first joint 100.

In another example, retaining means are formed prior to insertion of pivot member 104 in joint 100. In this example, the portion of bridge 32 that defines the aperture of joint 100 is elasto-plastically deformable. The aperture of joint 100 as defined by retaining means is sized to be smaller than the diameter pivot member 104. Pivot member 104 is pushed through the elasto-plastically deformable aperture defined by retaining means so as to place first pivot member 104 within first joint 100. Insertion of pivot member 104 causes the elasto-plastically deformable material to deform and reform (the elastic component of the deformation is recovered after the passage of the pivot member) once pivot member 104 is inserted. Thus, once pivot member 104 is inserted, retaining means reform to their initial size, and thereby reduce the size of the aperture so as to re-form retaining means. Following insertion of pivot member 104 the resulting aperture defined by retaining means is smaller than the diameter of pivot member 104. The size and/or shape of joint 100 remains sufficient to permit rotation of pivot member 104 within joint 100.

In operation, first pivot member 104 pivots around first inner surface 112 of first joint 100 as rocker arm 2 is actuated. It will be understood first pivot member 104 rotates and moves within first joint 100 so as to translate the force of rotation and translation during operation into the valve bridge during engine operation. For example, FIG. 5 depicts an example of movement of rocker arm 2 from a first position (Panel A) to a second position (Panel B), and the resulting rotation of first pivot member 104. However, in contrast to the first embodiment described above, the interaction of outer surface 122 of second pivot member 120 with second abutment surface 108 restrains rotation of first pivot member 104. It will be appreciated that the restraint to rotation of first pivot member 104 does not interfere with the rotation of first pivot member 104 within the angle of rotation required during normal engine operation.

It will be appreciated that the location of joint 16, first joint 100 and second joint 102 in the center portion of bridge 32 results in the equalization of the force applied to valve stems 22,22′, which is preferable as it can result decreased wear of the valve stems and increased life of valve stems (as compared to uneven force distribution to the valve stems). Joint 16, first joint 100 and second joint 102 and may be cast as part of bridge 32 or drilled into bridge 32. In one example, joint 16, first joint 100 and second joint 102 are cold formed in bridge 32. The configuration of the top and bottom surfaces of bridge 32 will be determined by the intended use, manufacturing considerations and/or engine application.

In another example, joint 16, first joint 100 and second joint 102 are configured to hold lubrication within the joint, so as to reduce the friction between the pivot member and joint during engine operation. Such lubrication can include engine oil or the like.

In another example of the present invention, the lash setting is made with a shim inserted between bridge 32 and rocker arm 2, which is facilitated as both abutment surface 26 and surface 14 are generally flat.

Alternate embodiments of the present invention are described in FIGS. 9 to 11.

In FIGS. 9 to 11, rocker arm 1002 is rotationally or pivotally mounted on a rocker shaft (not shown but generally noted by 1004). The configuration of rocker arm 1002 and the arrangement of rocker arm 1002 and rocker shaft 1004 are well known to the skilled worker. In some examples, rocker arm 1002 is configured to pivot on a pivot pin. In some examples, the rocker shaft of pivot pin is secured to a bracket mounted on the cylinder head. The size of rocker arm 1002 is determined by the intended use, needs of the application and/or manufacturing requirements, which can include the location of the intake and exhaust valves in relation to the rocker arm assembly. Rocker arms can be the same or different sizes, depending on the engine application. A variety of rocker arm assemblies and configurations may be used. For example, one or more rockers arm may be cooperatively mounted on a rocker carrier, which may be mounted on an engine.

One embodiment is shown in FIGS. 9 and 10.

As shown in FIG. 9, rocker arm 1002 has a second end (not shown) configured for attachment to pushrod (not shown), and a first end 1012 which comprises joint 1016 formed in rocker arm 1002. Joint 1016 defines a recess or cavity in rocker arm 1002 configured to receive pivot member 1024.

In the embodiment of FIGS. 9 and 10, valve bridge 1006 comprises bridge 1032 having surface 1014 formed on the outer surface of bridge 1032. Desirably, as shown, surface 1014 is disposed in a central portion of bridge 1032. Valve bridge 1006 further comprises bores 1018, 1018′ at ends 1020, 1020′ of bridge 1032. Bores 1018, 1018′ are configured to engage valve stems 1022, 1022′. Bridge 1032 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

Rocker arm 1002 further comprises pivot member 1024 disposed in joint 1016. Pivot member 1024 comprises abutment surface 1026 configured for cooperative association with surface 1014 on bridge 1032. Desirably, surface 1014 and abutment surface 1026 have a complementary shape or configuration which permits cooperative association between pivot member 1024 and bridge 1032. In a specific example, both abutment surface 1026 and surface 1014 are generally planar.

Pivot member 1024 further comprises curved portion 1028 configured so as to permit rotation of pivot member 1024 within joint 1016. In the example of FIGS. 9 and 10, curved portion 1028 is generally spherical. Pivot member 1024 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

As shown in FIGS. 9 and 10, joint 1016 comprises inner surface 1030, which in this Figure comprises generally planar walls and a generally conical base portion. Inner surface 1030 may obtained from a standard drilling operation and coining the bottom surface with a sphere having generally the same diameter as the joint 1016. Coining of the bottom surface improves the contact between the pivot member and the joint. Inner surface 1030 may be a variety of shapes or configurations, so long as pivot member 1024 is able to rotate within joint 1016.

In FIGS. 9 and 10, inner surface 1030 of joint 1016 is generally U-shaped, comprising a cylindrical wall 1030 a, which in this example are generally planar defining a cylinder, and a curved base 1030 b. In the Example of FIGS. 9 and 10, said curved base is a conical base.

In operation, pivot member 1024 pivots in joint 1016 around inner surface 1030 as rocker arm 1002 is actuated. It will be understood that pivot member 1024 rotates freely and moves within joint 1016 so as to translate the force of rocker arm 1002 into valve bridge 1006 during engine operation.

Thus, as rocker arm 1002 pivots during engine operation, rocker arm 1002 exerts force on valve bridge 1006, which in turn actuates valve movement in a cylinder (not shown).

In some examples, operative association of a cam shaft though, for example, a cam follower, pushrod, and the like, at the second end of rocker arm 1002 results in repeated movement of rocker arm 1002 so as to cause a swinging movement of rocker arm 1002.

The pivoting movement of rocker arm 1002 alternatively exerts a force on valve bridge 1006. As rocker arm 1002 pivots, abutment surface 1026 of pivot member 1024 in joint 1016 of rocker arm 1002 associates with surface 1014 of bridge 1032 so as translate the force from rocker arm 1002 to bridge 32, so as to and causes valves, which are in contact with valve bridge 1006 on their stem, to open. Thus, rotation of pivot member 1024 within joint 1016 permits the vertical motion of rocker arm 1002 to be translated into bridge 1032 during engine operation. In some examples, when rocker arm 1002 is released, the valves are pushed up by the force of valve-shutting springs and close.

The valve bridge and valve bridge mechanism of the present invention enables the rocker arm to operate two valves simultaneously.

FIG. 10 depicts another example in which rocker arm 1002 further comprises conduit 10400 within first end 1012 that is in communication with joint 1016 and the surface of rocker arm 1002. Conduit 10400 is sized to permit a tool (not show) to be inserted through conduit 10400 and remove pivot member 1024 and/or to act as a flow path to add lubrication, such as oil, to joint 1016.

An alternate embodiment is depicted in FIG. 11.

In FIG. 11, rocker arm 1002 includes first end 1012 which comprises first joint 100100 and second joint 100102. First joint 100100 and second joint 100102 are in communication. First joint 100100 defines a recess or cavity in rocker arm 1002 configured to receive first pivot member 100104. Second joint 100102 defines a recess or cavity configured to receive second pivot member 100120.

In the embodiment of FIG. 11, valve bridge 1006 comprises bridge 1032 having surface 1014 formed on the outer surface of bridge 1032. Desirably, as shown, surface 1014 is disposed in a central portion of bridge 1032. Valve bridge 1006 further comprises bores 1018, 1018′ at ends 1020, 1020′ of bridge 1032. Bores 1018, 1018′ are configured to engage valve stems 1022, 1022′. Bridge 1032 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

Rocker arm 1002 further comprises first pivot member 100104 disposed in first joint 100100 and second pivot member 100120 disposed in second joint 100102.

First pivot member 100104 comprises first abutment surface 100106 which cooperates with surface 1014 on bridge 1032 In a specific example, both first abutment surface 100106 and surface 1014 are generally planar. The complementary shape of first abutment surface 100106 and surface 1014 facilitate cooperation between the two parts. First pivot member 100104 further comprises second abutment surface 100108. In the example of FIG. 11, second abutment surface 100108 is generally planar. First pivot member 100104 further comprises curved or spherical portion 100110 configured so as to permit rotation of pivot member 100104 within first joint 100100. First pivot member 100104 can be made from a variety of materials, including but not limited to steel cast iron or aluminium.

As shown in FIG. 11, first inner surface 100112 of first joint 100100 comprising planar surfaces. In FIG. 11, first inner surface 100112 comprises walls 100112 a which are generally planar and generally conical base 100112 b. First inner surface 10012 may be obtained from a standard drilling operation and coining the bottom surface with a sphere having generally the same diameter as the first joint 100100. Coining of the bottom surface improves the contact between the pivot member and the joint. First inner surface 100112 may be a variety of shapes, so long as first pivot member 100104 is able to rotate with first joint 100100.

As shown in FIG. 11, rocker arm 1002 further comprises second pivot member 100120 disposed in second joint 100102. Outer surface 100122 of second pivot member 100120 is generally curved and cooperates with second abutment surface 100108 of first pivot member 100104.

In one example, outer surface 100122 is configured so as to permit rotation of second pivot member 100120 within second joint 100102. In another example, pivot member 100120 does not rotate within second joint 100102.

Second joint 100102 comprises second inner surface 100130, which comprises generally planar surfaces. Inner surface 100130 comprises walls 100130 a and generally conical base 100130 b.

Second pivot member 100120 can be a variety of shapes, so long as second pivot member 100120 is able to cooperate with second abutment surface 100108 and restrain rotation of first pivot member 100104. The restraint to the rotation of first pivot member 100104 helps in preventing or minimizing miss assembly in the engine. It will be appreciated that the restraint to rotation of first pivot member 100104 does not interfere with the rotation of first pivot member 100104 within the angle of rotation required during normal engine operation.

Second pivot member 100120 can be made from a variety of materials, including but not limited to steel, cast iron or aluminium.

As with the previous examples, and in the embodiments of FIGS. 9-11, in some examples, rocker arm 1002 further comprises retaining means (not shown) configured to retain pivot member 1024 or first pivot member 100104 within joint 1016 or first joint 100100, respectively. In one example (not shown), retaining means are integral with rocker arm 1002. In another example (not shown), retaining means are fixedly or removably attached to rocker arm 1002.

In one example, said retaining means are disposed at the aperture of said joint; the aperture of joint 1016 or first joint 100100 defined by retaining means is smaller than the diameter of pivot member 1024 or first pivot member 100104 and so retains pivot member 1024 or first pivot member 100104 within joint 1016 or first joint 100100, respectively.

Retaining means can be formed in a variety of ways. In one example, the retaining means are machined in place on rocker arm 1002 after pivot member 1024 or first pivot member 100104 is placed in joint 1016 or first joint 100100, respectively.

In another example, retaining means are formed prior to insertion of pivot member 1024 or first pivot member 100104 in joint 1016 or first joint 100100, respectively. In this example, the portion of rocker arm 1002 that defines the aperture of joint 1016 or first joint 100100 is elasto-plastically deformable. The aperture of joint 1016 or first joint 100100 as defined by retaining means is sized to be smaller than the diameter of pivot member 1024 or first pivot member 100104, respectively. Pivot member 1024 or first pivot member 100104 is pushed through the elasto-plastically deformable aperture defined by retaining means so as to place pivot member 1024 or first pivot member 100104 within joint 1016 or first joint 100100, respectively. Insertion of pivot member 1024 or first pivot member 100104 causes the elasto-plastically deformable material to deform and reform (the elastic component of the deformation is recovered after the passage of the pivot member) once pivot member 1024 or first pivot member 100104 is inserted. Thus, once pivot member 1024 or first pivot member 100104 is inserted, retaining means reform to their initial size, and thereby reduce the size of the aperture so as to re-form retaining means. Following insertion of pivot member 1024 or first pivot member 100104 the resulting aperture defined by retaining means is smaller than the diameter of pivot member 1024 or first pivot member 100104. The size and/or shape of joint 1016 or first joint 100100 remains sufficient to permit rotation of pivot member 1024 or first pivot member 100104, respectively, within joint 1016 or first joint 100100.

It will be appreciated the valve bridge and valve bridge mechanism as described herein can be used in a variety of internal combustion engines. For example, the valve bridge and valve bridge mechanism as described herein may be used in a 4-stroke cycle engine.

All publications, patents and patent applications mentioned in this Specification are indicative of the level of skill those skilled in the art to which this invention pertains and are herein incorporated by reference to the same extent as if each individual publication patent or patent application was specifically and individually indicated to be incorporated by reference.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modification as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1. A valve bridge, comprising: a bridge having a joint disposed in a central portion of said bridge; and a pivot member disposed within said joint, said pivot member comprising an abutment surface for cooperative association with a surface on a rocker arm and an outer surface portion configured for rotation within said joint, wherein said bridge is configured to engage two engine valves.
 2. The valve bridge of claim 1, wherein the inner surface of said joint is generally U-shaped comprising a generally cylindrical wall and a curved base.
 3. The valve bridge of claim 1, wherein the inner surface of said joint comprises (i) generally planar walls and a generally conical base, (ii) a generally conical base, or (iii) a generally curved base.
 4. The valve bridge of claim 1, further comprising retaining means configured to retain said pivot member with said joint.
 5. The valve bridge of claim 4, wherein said retaining means are disposed at the aperture of said joint.
 6. The valve bridge of claim 4, wherein said retaining means define an aperture in said joint which is less than the diameter of said pivot member.
 7. A valve bridge, comprising: a bridge having a first joint and a second joint disposed in a central portion of said bridge, said first and second joints are in communication; a first pivot member disposed in said first joint and a second pivot member disposed in said second joint, said first pivot member comprising a first abutment surface for cooperative association with a surface on a rocker arm, a second abutment surface, and an outer surface portion configured for rotation within said first joint, said second pivot member comprising an outer surface configured for rotation within said second joint and which cooperates with said second abutment surface of said first pivot member so as to restrain rotation of said first pivot member, wherein said bridge is configured to engage an engine valve.
 8. The valve bridge of claim 7, wherein the inner surface of said first joint comprises generally planar walls and a generally conical base.
 9. The valve bridge of claim 7, further comprising retaining means configured to retain said pivot member with said first joint.
 10. The valve bridge of claim 9, wherein said retaining means are disposed at the aperture of said joint.
 11. The valve bridge of claim 9, wherein said retaining means define an aperture in said joint which is less than the diameter of said pivot member.
 12. The valve bridge of claim 7, wherein said bridge further comprises a conduit in communication with said second joint and the outer surface of said bridge.
 13. A valve bridge, comprising: a bridge having a joint disposed in a central portion of said bridge; an abutment member positioned on the inner surface of said joint; and a pivot member disposed within said joint, said pivot member comprising a first abutment surface for cooperative association with a surface on a rocker arm, an outer surface portion configured for rotation within said joint, and a second abutment surface configured to restrain rotation of said pivot member within said join, wherein said bridge is configured to engage an engine valve.
 14. The valve bridge of claim 13, wherein said abutment member comprised a generally curved outer surface adapted for cooperative association with said second abutment surface of said pivot member.
 15. The valve bridge of claim 13, further comprising retaining means configured to retain said pivot member with said first joint.
 16. The valve bridge of claim 15, wherein said retaining means are disposed at the aperture of said joint.
 17. The valve bridge of claim 16, wherein said retaining means define an aperture in said joint which is less than the diameter of said pivot member.
 18. A valve train mechanism, comprising: a rocker arm having a joint disposed at a first end of said rocker arm; a pivot member disposed within said joint, said pivot member comprising an abutment surface and an outer surface portion configured for rotation within said joint; and a valve bridge comprising a surface disposed on a central portion of said valve bridge configured for cooperative association with said abutment surface on said pivot member; wherein said bridge is configured to engage two engines valves.
 19. The valve train mechanism of claim 18, wherein the inner surface of said joint is generally U-shaped comprising a generally cylindrical wall and a curved base.
 20. The valve train mechanism of claim 18, further comprising retaining means configured to retain said pivot member with said joint.
 21. The valve train mechanism of claim 20, wherein said retaining means are disposed at the aperture of said joint.
 22. A valve train mechanism, comprising: a rocker arm having a first end comprising a first joint and a second joint disposed at a first end of said rocker arm, said first and second joints are in communication; a first pivot member disposed in said first joint and a second pivot member disposed in said second joint, said first pivot member comprising an first abutment surface, a second abutment surface, and an outer surface portion configured for rotation within said first joint, said second pivot member comprising an outer surface configured for rotation within said second joint and which cooperates with said second abutment surface of said first pivot member so as to restrain rotation of said first pivot member; and a valve bridge comprising a surface in a central portion of said valve bridge, for cooperative association with said first abutment surface of said first pivot member, wherein said valve bridge is configured to engage an engine valve.
 23. The valve train mechanism of claim 22, further comprising retaining means configured to retain said first pivot member with said first joint.
 24. The valve train mechanism of claim 23, wherein said retaining means are disposed at the aperture of said joint.
 25. The valve train mechanism of claim 22, wherein said rocker arm further comprises a conduit in communication with said second joint and the outer surface of said rocker arm. 